Moving picture compression coding apparatus

ABSTRACT

A moving picture compression coding apparatus divides a screen into at least three regions and performs compression coding for the at least three regions by encoding units. The moving picture compression coding apparatus includes a coding control unit configured to control the encoding units to encode the data for different regions in parallel and to control the encoding such that the data for an upper region out of two adjacent upper and lower regions in the vicinity of the center of the screen of the at least three regions is encoded prior to the encoding of the data for the lower region or such that the data for a left region of two adjacent left and right regions in the vicinity of the center of the screen of the at least three regions is encoded prior to the encoding of the data for the right region.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a compression coding apparatus formoving picture data, and in particular, to a technique suited for use individing a screen and encoding the moving picture data of the dividedscreen in parallel by use of a plurality of encoding units.

2. Description of the Related Art

Digital video cameras are well known as a moving picture recordingapparatus that has an integrated camera and that obtains an image of asubject, performs compression coding on the obtained moving picturedata, and records the moving image data. Instead of traditional magnetictape, a randomly accessible highly convenient disk medium orsemiconductor memory is becoming used in a recent digital video camera.However, in general, disk media have a small amount of memory capacity,so it is necessary to perform compression coding with a high degree ofefficiency.

These days, with the expectations for high image quality, a digitalvideo camera that deals with a high-definition (HD) image, which has alarger amount of information than that of a standard image, is beingdeveloped. Therefore, also from the viewpoint of an increased amount ofinformation of an image in itself, compression coding with a high degreeof efficiency is necessary. Currently, the moving picture experts group(MPEG) scheme is often used as a standard technique for compressioncoding. In the MPEG scheme, encoding with a high degree of efficiency isrealized by motion compensation prediction using a plurality of screensconstituting a moving picture. To do this, it is necessary to processenormous volumes of image data at high speed.

If an encoding circuit operates with significantly high speed to performthe above-described high-speed processing, a problem exists in which theload becomes heavy and power consumption is increased. One example of animage coding apparatus that aims to solve this problem is described inJapanese Patent Laid-Open No. 7-095572. This apparatus solves the aboveproblem by dividing each screen in a motion image signal into aplurality of regions and encoding the image signal divided into theregions in parallel using a plurality of encoding units.

When each screen in a motion image signal is divided into a plurality ofregions and the regions are subjected to encoding in parallel by aplurality of encoding units, as described above, image quality may varyin a boundary portion of adjacent regions. The image coding apparatusdescribed in Japanese Patent Laid-Open No. 7-095572 divides an imagesignal into small regions in a second division direction different fromthe direction of the above division and controls an encoding parameterfor use by each of the encoding units for each of the small regionsformed in the second division direction. The image coding apparatusmakes degradation in image quality in the boundary portion of the smallregions less noticeable by encoding the small regions using the sameencoding parameter.

However, the image coding apparatus described in Japanese PatentLaid-Open No. 7-095572 controls the encoding parameter for each of thesmall regions formed by dividing of the screen in two differentdirections. Therefore, a predetermined set value is undesirablydetermined as the encoding parameter for each of the regions, so it isdifficult to use an encoding parameter suited for the characteristics ofan image.

SUMMARY OF THE INVENTION

The present invention provides a technique for making degradation inimage quality in a boundary portion of regions into which a screen isdivided and encoded less noticeable using a simple structure and forproviding the capability of setting an encoding parameter suited for thecharacteristics of an image.

According to an aspect of the present invention, a moving picturecompression coding apparatus includes a region segmentation unit, aplurality of encoding units, an encoded-data combining unit, and acoding control unit. The region segmentation unit is configured tohorizontally divide a screen constituting moving picture data into atleast three regions. The plurality of encoding units are configured toencode the moving picture data for each of the regions to form encodeddata elements, a number of the encoding units being smaller than anumber of the regions. The encoded-data combining unit is configured tocombine the encoded data elements. The coding control unit is configuredto control the plurality of encoding units to encode the moving picturedata for different regions in parallel and control the encoding suchthat the moving picture data for an upper region out of two adjacentupper and lower regions located in a vicinity of a center of the atleast three regions is encoded prior to the encoding of the movingpicture data for the lower region.

According to another aspect of the present invention, a moving picturecompression coding apparatus includes a region segmentation unit, aplurality of encoding units, an encoded-data combining unit, and acoding control unit. The region segmentation unit is configured tovertically divide a screen constituting moving picture data into atleast three regions. The plurality of encoding units are configured toencode the moving picture data for each of the regions to form encodeddata elements, a number of the encoding units being smaller than anumber of the regions. The encoded-data combining unit is configured tocombine the encoded data elements. The coding control unit is configuredto control the plurality of encoding units to encode the moving picturedata for different regions in parallel and control the encoding suchthat the moving picture data for a left region out of two adjacent leftand right regions located in a vicinity of a center of the screen of theat least three regions is encoded prior to the encoding of the movingpicture data for the right region.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram that illustrates a structure of a movingpicture coding apparatus according to a first embodiment of the presentinvention.

FIG. 2 illustrates an example of how a screen is divided according tothe first embodiment.

FIG. 3 illustrates an example encoding order according to the firstembodiment.

FIG. 4 is a block diagram that illustrates a detailed structure of afirst encoding circuit according to embodiments of the presentinvention.

FIG. 5 illustrates an example operating procedure of the moving picturecoding apparatus according to the embodiments of the present invention.

FIG. 6 is a block diagram that illustrates a structure of the movingpicture coding apparatus according to a second embodiment of the presentinvention.

FIG. 7 illustrates an example of how a screen is divided according tothe second embodiment.

FIG. 8 illustrates an example encoding order according to the secondembodiment.

DESCRIPTION OF THE EMBODIMENTS

Numerous embodiments, features and aspects of the present invention willbe described with reference to the drawings.

First Embodiment

FIG. 1 is a block diagram that illustrates a structure of a movingpicture coding apparatus according to a first embodiment of the presentinvention. The moving picture coding apparatus in the present embodimentperforms compression coding on moving picture data using motioncompensation prediction. The moving picture coding apparatus in thepresent embodiment is applicable to an image pickup device, such as adigital video camera.

In FIG. 1, the moving picture coding apparatus 100 includes an imagesignal input terminal 101 configured to receive moving picture data(image signal) input from, for example, an image pickup unit (notshown). The moving picture coding apparatus 100 also includes a regionsegmentation circuit 102 configured to divide a one-field or one-frameimage signal in a moving picture into n regions, a first encodingcircuit 103 a, and a second encoding circuit 103 b. The first and secondencoding circuits 103 a and 103 b each perform encoding using motioncompensation prediction that utilizes motion compensation of an imagesignal.

The moving picture coding apparatus 100 also includes an encoded-datacombining circuit 105 configured to combine encoded data elements outputfrom the first and second encoding circuits 103 a and 103 b. The movingpicture coding apparatus 100 further includes a coding control circuit106 configured to control an encoding parameter on the basis of a resultof the encoding output from the first and second encoding circuits 103 aand 103 b. The moving picture coding apparatus 100 also includes anencoded-data output terminal 107 configured to output combined encodeddata to a storage medium or a communication channel (not shown).

The first and second encoding circuits 103 a and 103 b operate inparallel by control of the coding control circuit 106. Operation of eachof the above-described components is controlled by a system controller104. An actual moving picture coding apparatus needs other components,but the description thereof is omitted here because they are not a mainpoint of the present invention.

Operation of the moving picture coding apparatus 100 will now bedescribed below. FIG. 5 is a flowchart that illustrates an exampleoperating procedure of the moving picture coding apparatus according tothe embodiments of the invention. When an image signal received in theimage signal input terminal 101 in units of fields or frames is inputinto the region segmentation circuit 102, the process illustrated in theflowchart starts.

First, in step S501, the region segmentation circuit 102 divides eachscreen 200 included in an input image signal into four regions (a firstarea 201 (Area 1) to a fourth area 204 (Area 4)) in units of slices, asillustrated in FIG. 2. The slice is a unit of an encoding processingthat the first and second encoding circuits 103 a and 103 b performs.FIG. 2 illustrates an example of how one screen is divided into fourportions along predetermined pixel lines in a horizontal direction. Inthe present embodiment, the number of encoding circuits, m, is two, andthe number of divisions, i.e., regions formed by dividing performed bythe region segmentation circuit 102, n (n is an integer greater thantwo; n>2), is four.

In step S502, the coding control circuit 106 determines an encodingcircuit that is to perform encoding for each of the first area 201 tothe fourth area 204 out of the plurality of encoding circuits and atemporal encoding order.

In step S503, the first and second encoding circuits 103 a and 103 bperform encoding for their respective assigned regions. At this time,the coding control circuit 106 controls the first and second encodingcircuits 103 a and 103 b to perform their respective encoding processesin parallel. Then, in step S504, the encoded-data combining circuit 105combines encoded data elements formed by encoding performed by the firstand second encoding circuits 103 a and 103 b and outputs the combinedencoded data to the encoded-data output terminal 107, and the processingis completed.

In the present embodiment, the coding control circuit 106 makes anencoding process of slices included in one frame complete for one frameperiod of an input image signal. That is, the coding control circuit 106controls the first and second encoding circuits 103 a and 103 b toencode image data elements for two regions out of the four regions at atime in parallel and controls each of the first and second encodingcircuits 103 a and 103 b to encode the image data elements for the tworegions in one frame. Each of the first and second encoding circuits 103a and 103 b performs the encoding in a time division manner such thatone frame is separated into the first and second halves, as illustratedin FIG. 3. That is, the image data elements for a plurality of regionsout of the first area 201 to the fourth area 204 are encoded in parallelprior to the encoding for the remaining regions.

In the first half of a frame period, the coding control circuit 106controls the first encoding circuit 103 a to encode the data for thesecond area 202 (Area 2) and the second encoding circuit 103 b to encodethe data for the first area 201 (Area 1) in parallel therewith. In thesecond half of the frame period, the coding control circuit 106 controlsthe first encoding circuit 103 a to encode the data for the third area203 (Area 3), which is adjacent to the second area 202, and the secondencoding circuit 103 b to encode the data for the fourth area 204 (Area4) in parallel therewith. When the portions located in the vicinity ofthe center of the screen are noted, the data for the upper region (Area2) is encoded prior to the encoding of the data for the lower region(Area 3).

In encoding control, the coding control circuit 106 sets an initialvalue of a quantization step size being an encoding parameter for eachof the encoding circuits. The encoding for each area is performed insequence from above in units of predetermined pixel blocks (e.g.,macroblocks). Therefore, in the present embodiment, to determine theinitial value of the quantization step size in the third area 203, thequantization step size for the last block in the second area 202 isreferred to from a result of encoding for the second area 202.Specifically, the coding control circuit 106 holds the quantization stepsize for the last block in the second area 202, and sets thequantization step size for the last block in the second area 202 as theinitial value of the quantization step size for a block to be firstencoded in the third area 203. Such encoding control enables thecontinuity between the quantization step size in the second area 202located in the vicinity of the center of the screen and that in thethird area 203, which is adjacent to the second area 202, to be ensured.Accordingly, the continuity of image quality in the vicinity of thecenter of the screen, where differences in image quality are prone tobeing visually recognized, can be ensured.

The first area 201 and the fourth area 204, which are not located in thevicinity of the center of the screen, are remote from each other.Therefore, the optimal quantization step size suited for thecharacteristics of an image can be set through encoding control for eacharea on the basis of the details of a block to be encoded.

As described above, in the present embodiment, the encoding order andthe encoding parameters are determined such that the continuity of imagequality between areas located in the vicinity of the center of thescreen is ensured. As a result, the number n of divisions (regionsformed by a dividing process) is set at a value larger than the number mof encoding circuits. If the number n of divisions is set at a highnumber, the difference in image quality in boundary portions of regionsthat are not located in the vicinity of the center of the screen may besignificantly large. To avoid this, the number n of divisions is betterset at a value not exceeding twice the number m of encoding circuits.That is, one encoding circuit does not perform encoding for three ormore areas.

Operation of the first and second encoding circuits 103 a and 103 b willnow be described below. Each of the first and second encoding circuits103 a and 103 b considers a region formed by a dividing process (slice)as one unit in an encoding process and performs encoding for each region(slice).

FIG. 4 is a block diagram that illustrates a detailed structure of thefirst encoding circuit 103 a according to the embodiments of the presentinvention. The structure of the second encoding circuit 103 b issubstantially the same as that of the first encoding circuit 103 a, sothe description is omitted here.

In FIG. 4, the first encoding circuit 103 a includes an input terminal401 configured to receive an image signal, a frame memory 402, a motionvector search circuit 403, an inter-frame motion compensation circuit404, an intra prediction circuit 405, and a switch 406. The firstencoding circuit 103 a also includes a subtractor 407, an integertransform circuit 408, a quantization circuit 409, an inversequantization circuit 410, an inverse integer transform circuit 411, anadder 412, and an in-loop filter 413. The first encoding circuit 103 afurther includes an entropy encoding circuit 415, a coding amountcontrol circuit 416, and an output terminal 417 through which encodeddata is output. Operation of each of these components, including thecoding amount control circuit 416, is controlled by the systemcontroller 104.

An image signal input into the input terminal 401 is stored in the framememory 402 in the order of a first frame, a second frame, a third frame,. . . in the case of a frame unit. The image signal is extracted fromthe frame memory 402 in the order of, for example, the third frame, thefirst frame, the second frame, . . . , i.e., the order in which encodingis to be performed.

Examples of an encoding system are “intra encoding” which uses onlyintra-frame image data (in the case of slice, only intra-slice imagedata) and “inter encoding” which also employs inter-frame prediction.Pictures (frames) subjected to the inter encoding are P pictures inwhich prediction is made to one reference frame in units of motioncompensation (MC blocks) and B pictures in which prediction is made toup to two reference frames. Pictures subjected to the intra predictionare called I pictures. The reason why the order in which frames aresubjected to encoding differs from the order in which the frames areinput is to make prediction of a future frame in terms of time (backwardprediction) possible.

When the intra encoding is performed, an image block to be encoded isread from the frame memory 402 and input into the intra predictioncircuit 405. The intra prediction circuit 405 conducts block matching ofa block to be encoded (image to be encoded) against a plurality ofpredicted images composed of local decoded images (described later)located in the vicinity of the block to be encoded within the sameframe. An intra-predicted image that has the highest correlation isselected and output to the switch 406.

In the present embodiment, as previously described, the data elementsfor the two adjacent regions located above and below the centralposition of the screen (the second area 202 and the third area 203) areencoded by the same encoding circuit. That encoding circuit performsencoding for the third area 203 (the region below the center) afterperforming encoding for the second area 202 (the region above thecenter). In addition, when the third area 203 is encoded, the framememory 402 holds at least data of a local decoded image for thelowermost block in the encoded second area 202. A local decoded imagefor the lowermost block in the encoded second area 202 is used in intraprediction performed on the topmost block in the third area 203.Information about, for example, the direction of the intra prediction onthe lowermost block in the encoded second area 202 may be referred to inthe intra prediction of the topmost block in the third area 203. Suchinformation about a block for use in the intra prediction or informationabout the direction of the prediction can also be set in encoding as oneof the encoding parameters.

When the intra encoding is performed, the switch 406 is switched to aside that handles an intra-predicted image, and the intra-predictedimage is output to the subtractor 407. The subtractor 407 extractsdifferential information between the pixel value of the image to beencoded output from the frame memory 402 and that of the intra-predictedimage received from the switch 406 and outputs the differentialinformation to the integer transform circuit 408.

The integer transform circuit 408 performs integer transform (frequencyconversion) on the differential information in the pixel value andtransmits a conversion coefficient to the quantization circuit 409.Then, the quantization circuit 409 quantizes the input conversioncoefficient. The entropy encoding circuit 415 performs entropy coding onthe conversion coefficient quantized by the quantization circuit 409 andthen outputs it to the encoded-data combining circuit 105 via the outputterminal 417.

The quantization step size for use by the quantization circuit 409 iscalculated by the coding amount control circuit 416 from feedback aboutthe amount of encoding occurring in the entropy encoding circuit 415.The initial value of the quantization step size is set by the codingcontrol circuit 106.

The inverse quantization circuit 410 inversely quantizes the conversioncoefficient quantized by the quantization circuit 409, and the inverselyquantized one is subjected to inverse integer transform performed by theinverse integer transform circuit 411. The adder 412 adds theintra-predicted image output from the switch 406 and differentialinformation in pixel value subjected to the inverse integer transformperformed by the inverse integer transform circuit 411 together togenerate a local decoded image. The local decoded image is input intothe intra prediction circuit 405 and used in generation of anintra-predicted image. After the local decoded image is subjected to aprocess for reducing coding artifacts performed by the in-loop filter413, the local decoded image is stored in the frame memory 402 as areference image for use in the inter encoding, which will be describedbelow.

In contrast, when the inter encoding is performed, an image block to beencoded is read from the frame memory 402 and input into the motionvector search circuit 403. The motion vector search circuit 403 readsthe above-described reference image from the frame memory 402 anddetects a motion vector from the image to be encoded and the referenceimage. The inter-frame motion compensation circuit 404 performs motioncompensation according to the motion vector detected by the motionvector search circuit 403 and generates the inter-predicted image.

When the inter encoding is performed, the switch 406 is switched to aside that handles an inter-predicted image, and the inter-predictedimage is output to the subtractor 407. The subtractor 407 extracts adifferential image between the image to be encoded and theinter-predicted image and outputs the extracted differential image tothe integer transform circuit 408. The other processing is substantiallythe same as that in the intra encoding described above, so thedescription is not repeated here.

As described above, in the present embodiment, the first and secondencoding circuits 103 a and 103 b perform their encoding processes inparallel, and the encoding for the second area 202 located in thevicinity of the center of the screen is performed prior to the encodingfor the third area 203. The encoding order and encoding parameters aredetermined such that the continuity of image quality between areaslocated in the vicinity of the center of the screen is ensured. Thisenables information about a result of encoding to be shared and thecontinuity of image quality in the vicinity of the center of the screen,where differences in image quality are prone to being visuallyrecognized, to be ensured, without having to significantly increase theoperation speed of each of the encoding circuits. Accordingly,degradation in image quality can be made less noticeable, and theoptimal encoding parameters suited for the characteristics of an imagecan be set.

Second Embodiment

FIG. 6 is a block diagram that illustrates a structure of the movingpicture coding apparatus according to a second embodiment of the presentinvention. The moving picture coding apparatus in the present embodimentperforms compression coding on moving picture data using motioncompensation prediction, as in the case of the first embodiment. Themoving picture coding apparatus in the present embodiment is alsoapplicable to an image pickup device, such as a digital video camera.

In FIG. 6, the moving picture coding apparatus 600 includes a regionsegmentation circuit 602, in place of the region segmentation circuit102 included in the moving picture coding apparatus 100 illustrated inFIG. 1, and further includes a frame memory 601. Of the componentsillustrated in FIG. 6, the components having the same reference numeralsas those of the components illustrated in FIG. 1 are substantially thesame as in FIG. 1, so the description thereof is omitted here.

Operation of the moving picture coding apparatus 600 will now bedescribed below with reference to the flowchart of FIG. 5 previouslydescribed.

When an image signal received in the image signal input terminal 101 inunits of fields or frames is temporarily stored in the frame memory 601.In step S501, the region segmentation circuit 602 divides a frame image(screen 700) stored in the frame memory 601 four regions (a fifth area701 (Area 5) to an eighth area 704 (Area 8) in units of slices, asillustrated in FIG. 7. FIG. 7 illustrates an example of how one screenis divided into four portions at predetermined locations in a verticaldirection. In the present embodiment, the number of encoding circuits,m, is two, and the number of divisions, i.e., regions formed by dividingperformed by the region segmentation circuit 602, n (n is an integergreater than two; n>2), is four.

In step S502, the coding control circuit 106 determines an encodingcircuit that is to perform encoding for each of the fifth area 701 tothe eighth area 704 out of the plurality of encoding circuits and atemporal encoding order.

In step S503, the first and second encoding circuits 103 a and 103 bperform encoding for their respective assigned regions. At this time,the coding control circuit 106 controls the first and second encodingcircuits 103 a and 103 b to perform their respective encoding processesin parallel. Then, in step S504, the encoded-data combining circuit 105combines encoded data elements formed by encoding performed by the firstand second encoding circuits 103 a and 103 b and outputs the combinedencoded data to the encoded-data output terminal 107, and the processingis completed.

In the present embodiment, the coding control circuit 106 makes anencoding process of slices included in one frame complete for one frameperiod of an input image signal. That is, the coding control circuit 106controls the first and second encoding circuits 103 a and 103 b toencode image data elements for two regions out of the four regions at atime in parallel and controls each of the first and second encodingcircuits 103 a and 103 b to encode the image data elements for the tworegions in one frame. Each of the first and second encoding circuits 103a and 103 b performs the encoding in a time division manner such thatone frame is separated into the first and second halves, as illustratedin FIG. 8. That is, the image data elements for a plurality of regionsout of the fifth area 701 to the eighth area 704 are encoded in parallelprior to the encoding for the remaining regions.

In the first half of a frame period, the coding control circuit 106controls the first encoding circuit 103 a to encode the data for thesixth area 702 (Area 6) and the second encoding circuit 103 b to encodethe data for the fifth area 701 (Area 5) in parallel therewith. In thesecond half of the frame period, the coding control circuit 106 controlsthe first encoding circuit 103 a to encode the data for the seventh area703 (Area 7), which is adjacent to the sixth area 702, and the secondencoding circuit 103 b to encode the data for the eighth area 704 (Area8) in parallel therewith. When the portions located in the vicinity ofthe center of the screen are noted, the data for the left region (Area6) is encoded prior to the encoding of the data for the right region(Area 7).

In encoding control, the coding control circuit 106 sets an initialvalue of a quantization step size being an encoding parameter for eachof the encoding circuits. The encoding for each area is performed insequence in units of predetermined pixel blocks (e.g., macroblocks). Forthe encoding order for pixel blocks, the encoding is performed from leftto right in the topmost line of an area, then from left to right in thesecond line, . . . , to the last line. Therefore, in the presentembodiment, to determine the initial value of the quantization step sizefor the leftmost block in the seventh area 703, a result of encoding forthe rightmost block in the same line in the encoded sixth area 702 isreferred to. Specifically, the coding control circuit 106 holds thequantization step size for the rightmost block in the sixth area 702,and sets the quantization step size for the rightmost block in the sixtharea 702 as the initial value of the quantization step size for theleftmost block in the seventh area 703. Such encoding control enablesthe continuity between the quantization step size in the sixth area 702located in the vicinity of the center of the screen and that in theseventh area 703, which is adjacent to the sixth area 702, to beensured. Accordingly, the continuity of image quality in the vicinity ofthe center of the screen, where differences in image quality being proneto being visually recognized, can be ensured.

The fifth area 701 and the eighth area 704, which are not located in thevicinity of the center of the screen, are remote from each other.Therefore, the optimal quantization step size suited for thecharacteristics of an image can be set through encoding control for eacharea on the basis of the details of a block to be encoded.

The structure of each of the first and second encoding circuits 103 aand 103 b and the detailed encoding process are substantially the sameas those in the first embodiment, which is previously described withreference to FIG. 4, so the description thereof is not repeated here.

In the present embodiment, as previously described, the data elementsfor the two adjacent regions located on the left and the right of thecentral position of the screen (the sixth area 702 and the seventh area703) are encoded by the same encoding circuit. That encoding circuitperforms encoding for the seventh area 703 (the region on the right ofthe center) after performing encoding for the sixth area 702 (the regionon the left of the center). In addition, when the seventh area 703 isencoded, the frame memory 402 holds at least data of a local decodedimage for the rightmost block in the encoded sixth area 702. A localdecoded image for the rightmost block in the encoded sixth area 702 isused in intra prediction performed on the leftmost block in the seventharea 703. Information about, for example, the direction of the intraprediction on the rightmost block in the encoded sixth area 702 may bereferred to in the intra prediction of the leftmost block in the seventharea 703. Such information about a block for use in the intra predictionor information about the direction of the prediction can also be set inencoding as one of the encoding parameters.

As described above, in the present embodiment, the first and secondencoding circuits 103 a and 103 b perform their encoding processes inparallel, and the encoding for the sixth area 702 located in thevicinity of the center of the screen is performed prior to the encodingfor the seventh area 703. The encoding order and encoding parameters aredetermined such that the continuity of image quality between areaslocated in the vicinity of the center of the screen is ensured. Thisenables information about a result of encoding to be shared and thecontinuity of image quality in the vicinity of the center of the screen,where differences in image quality are prone to being visuallyrecognized, to be ensured, without having to significantly increase theoperation speed of each of the encoding circuits. Accordingly,degradation in image quality can be made less noticeable, and theoptimal encoding parameters suited for the characteristics of an imagecan be set.

Other Embodiments

The units included in the moving picture coding apparatus according tothe embodiments of the present invention and the steps in the movingpicture coding method can be realized by execution of a program storedin a random-access memory (RAM) of a computer or read-only memory (ROM).The program and a computer-readable storage medium that stores theprogram are included in the scope of the present invention.

According to an aspect of the present invention, an embodiment servingas, for example, a system, an apparatus, a method, a program, or astorage medium is also possible. Specifically, the present invention isapplicable to a system including a plurality of devices and also to anapparatus consisting of a single device.

The scope of the present invention includes a case where a softwareprogram that realizes the functions of at least one of the foregoingembodiments (in the embodiments, a program corresponding to theflowchart of FIG. 5) is supplied directly or remotely to a system or anapparatus. The scope of the present invention also includes a case wherethe functions are realized by a computer of the system or the apparatusreading and executing the supplied program code.

Accordingly, code itself (to be) installed in the computer to performthe functional processing of at least one of the embodiments of thepresent invention by use of the computer is also included in the scopeof the present invention. That is, the scope of the present inventionincludes a computer program itself for performing the functionalprocessing of at least one of the embodiments of the present invention.

In this case, the program may have any form, such as object code, aprogram executable by an interpreter, or script data suppliable to anoperating system, as long as it has functions of the program.

Examples of a storage medium for supplying a program include a floppydisk, a hard disk, an optical disk, a magneto-optical disk (MO), acompact-disk read-only memory (CD-ROM), a compact disk recordable(CD-R), a CD-Rewritable (CD-RW), magnetic tape, a nonvolatile memorycard, a ROM, and a digital versatile disk (DVD), such as a DVD-ROM and aDVD-R.

One example of a method for supplying a program is to cause a user toaccess a website on the Internet using a browser of a client computerand to download a computer program itself or a file that includes acompressed program with an automatic installer from the website into astorage medium (e.g., a hard disk).

Program code constituting a program according to an aspect of thepresent invention may be divided into a plurality of files and the filesmay be downloaded from different websites. That is, a world wide web(WWW) server causing a plurality of users to download a program forexecuting the functional processing of at least one of the embodimentsof the present invention by a computer is also included in the scope ofthe present invention.

The functions of at least one of the embodiments can also be realized byanother method including distributing a program corresponding to anaspect of the present invention to users through storage media, such asCD-ROMs, that store its encrypted program, causing a user who satisfiesa predetermined condition to download information regarding a decryptionkey from a website over the Internet, and executing the encryptedprogram using the key information and installing it in a computer.

The functional processing of at least one of the foregoing embodimentcan be realized by a computer reading and executing a program.Performing actual processing in part or in entirety by an operatingsystem (OS) running on a computer in accordance with instructions of theprogram can realize the functions of at least one of the foregoingembodiments.

The functions of at least one of the foregoing embodiments can also berealized by still another method including writing a program read from astorage medium on a memory included in a function expansion boardinserted into a computer or a function expansion unit connected to acomputer and then executing actual processing in part or in entirety byuse of a central processing unit (CPU) included in the functionexpansion board or the function expansion unit in accordance withinstructions of the program.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all modifications and equivalent structures and functions.

This application claims the benefit of Japanese Application No.2007-160379 filed Jun. 18, 2007 and No. 2008-120407 filed May 2, 2008,which are hereby incorporated by reference herein in their entirety.

What is claimed is:
 1. A moving picture compression coding apparatuscomprising: a region segmentation circuit that horizontally divides ascreen constituting moving picture data into a plurality of regions; aplurality of encoding circuits that encode the moving picture data foreach of the regions to form encoded data elements, the number of theencoding circuits being smaller than the number of the regions in thescreen divided by the region segmentation circuit; an encoded-datacombining circuit that combines the encoded data elements; and a codingcontrol circuit that controls the plurality of encoding circuits toencode the moving picture data for a plurality of regions in the screenin parallel and controls the plurality of encoding circuits so that afirst encoding circuit consecutively encodes two regions which areadjacently located one above the other and each of which is neither anuppermost region nor a lowermost region, wherein the first encodingcircuit does not encode the uppermost region and the lowermost region,and wherein, within a frame period, the first encoding circuit encodesthe lower region of the two adjacent regions after encoding of the upperregion of the two adjacent regions is finished.
 2. The moving picturecompression coding apparatus according to claim 1, wherein each of theplurality of encoding circuits includes a frequency conversion circuitthat performs frequency conversion on a block to be encoded in themoving picture data and a quantization circuit that quantizes aconversion coefficient obtained by the frequency conversion using apredetermined quantization step size, and the first encoding circuitsets an initial value of the quantization step size for use by thequantization circuit for the lower region in accordance with a result ofthe encoding of the moving picture data for the upper region.
 3. Themoving picture compression coding apparatus according to claim 1,wherein the region segmentation circuit divides the screen into slices,and each of the plurality of encoding circuits compresses the pluralityof regions dividing the screen into slices using motion compensationprediction.
 4. The moving picture compression coding apparatus accordingto claim 1, wherein the region segmentation circuit divides the screeninto slices, and each of the plurality of encoding circuits compressesthe plurality of regions dividing the screen into slices using intraprediction.
 5. The moving picture compression coding apparatus accordingto claim 4, wherein the first encoding circuit sets an encodingparameter relating to the intra prediction for a topmost block to beencoded in the lower region in accordance with information of alowermost block to be encoded in the upper region.
 6. A moving picturecompression coding apparatus comprising: a region segmentation circuitthat vertically divides a screen constituting moving picture data into aplurality of regions; a plurality of encoding circuits that encode themoving picture data for each of the regions to form encoded dataelements, the number of the encoding circuits being smaller than thenumber of the regions in the screen divided by the region segmentationcircuit; an encoded-data combining circuit that combines the encodeddata elements; and a coding control circuit that controls the pluralityof encoding circuits to encode the moving picture data for a pluralityof regions in the screen in parallel and controls the plurality ofencoding circuits so that a first encoding circuit consecutively encodestwo regions which are adjacently located side to side and each of whichis neither a rightmost region or a leftmost region, wherein, within aframe period, the first encoding circuit encodes the right region of thetwo adjacent regions after encoding of the left region of the twoadjacent regions is finished.
 7. The moving picture compression codingapparatus according to claim 6, wherein each of the plurality ofencoding circuits includes a frequency conversion circuit that performsfrequency conversion on a block to be encoded in the moving picture dataand a quantization circuit that quantizes a conversion coefficientobtained by the frequency conversion using a predetermined quantizationstep size, and the first encoding circuit sets an initial value of thequantization step size for use by the quantization circuit for aleftmost block to be encoded in the right region in accordance with aresult of the encoding of the moving picture data for a rightmost blockto be encoded in the left region.
 8. The moving picture compressioncoding apparatus according to claim 6, wherein the region segmentationcircuit divides the screen into slices, and each of the plurality ofencoding circuits compresses the plurality of regions dividing thescreen into slices using motion compensation prediction.
 9. The movingpicture compression coding apparatus according to claim 6, wherein theregion segmentation circuit divides the screen into slices, and each ofthe plurality of encoding circuits compresses the plurality of regionsdividing the screen into slices using intra prediction.
 10. The movingpicture compression coding apparatus according to claim 9, wherein thefirst encoding circuit sets an encoding parameter relating to the intraprediction for the leftmost block to be encoded in the right region inaccordance with information about a rightmost block to be encoded in theleft region.
 11. A moving picture compression coding apparatuscomprising: a region segmentation circuit that divides a screenconstituting moving picture data into a plurality of regions; aplurality of encoding circuits that encode the moving picture data forthe regions; and a coding control circuit that controls the plurality ofencoding circuits to encode the moving picture data for a plurality ofregions in the screen in parallel and controls the plurality of encodingcircuits so that a first encoding circuit encodes the moving picturedata for two predetermined adjacent regions of the plurality of regionsconsecutively, wherein each of the two predetermined adjacent regions isnone of the uppermost region, the lowermost region, the leftmost regionand the rightmost region, and wherein, within a frame period, the firstencoding circuit uses a result of encoding on one of the predeterminedadjacent regions whose data is previously encoded in encoding on theother of the predetermined adjacent regions whose data is subsequentlyencoded.